Apple Pencil is great, expensive, but still the best digital pen option for iPads. Managing it’s battery life needs simple trickery.
The Apple Pencil doesn’t have an on/off option. That means that the Pencil keeps a connection and drains a little battery life all the time. When the Pencil is new, that’s not a problem. It can be a nuisance as the device gets older and the Pencil battery can’t keep a charge for as long.
In theory, Apple Pencil should shut down if left idle for some time. However, in practice, the Pencil seems to stay connected for many hours or days despite no use.
There are two ways to disconnect an Apple Pencil so it’s not ‘live’ until you need it. If you don’t use the Pencil a lot, there are ways to keep it off until needed.
Turn off Bluetooth
Go to Settings | Bluetooth and turn it off.
Switch Bluetooth on when you need the Apple Pencil. Turning Bluetooth off will also help preserve the iPad battery life, just a little.
That’s OK if the Apple Pencil is the only Bluetooth device connected to the iPad.
‘Forget’ the Apple Pencil
If you have other Bluetooth connections or needs (keyboard, AirDrop etc) then there’s only one way to disconnect the Pencil, forget it. Or rather make the iPad ‘forget’ it’s connection to the Apple Pencil.
Go to Settings | Bluetooth (turned on). Look for Apple Pencil in the list of devices and click the little (i) icon on the right. Then select ‘Forget this Device’.
The Apple Pencil might appear in the ‘Other devices’ list for a short time but it’ll disappear when the Pencil shuts down completely.
To reconnect, just plug the Apple Pencil into the iPad Lightning slot. That will re-pair the connection.
Neither option is ideal. It’s what Apple has given their customers. Their focus is on instant availability of the Apple Pencil not extending its battery life.